Improvement in flasks for casting steel ingots



UNITED STATES g PATENT OFFICE.

ZOHETH SHERMAN DURFEE, OF PITTSBURG, PENNSYLVANIA.

IMPROVEMENT IN FI..ASKS FOR CASTING STEEL INGOTS.

Specication forming part of Letters Patent No. 56,388, dated July 17,1866.

To all 'whom fit may concern:

Beit known that I, ZoHE'rH SHERMAN DUR- FEE, of Pittsburg, in the county of Allegheny, in the State of Pennsylvania, have invented a new and Improved Mode of Casting Ingots of Steel or other Metals; and I do hereby declare that the following is a full and eXact description thereof, reference being had to the accompanying drawings, and to the letters of reference thereon.

The drawings show the ingot-'mold as placed in' a casting-pit.

Figure l represents a vertical section of the ingot-mold piston and one of the pipes connected with it. Fig. 2 is a horizontal section of the mold through the piston on the line t b and Fig. 3 is a horizontal section of a mold, showing a method of making it in two halves, which may be found desirable iu some cases.

Ihe mold may be made of any convenient section, but preferably cylindrical. It should be closed tightly at the bottom, and the piston should it as loosely in it as it will be possible to have it and still prevent metal from flowing down between its sides and those of the mold. Air or water beneath the piston may be prevented from iiowing up around it and into the upper part of the mold byacup-valve of leather attached to the bottom of the piston and fitting closely against the sides of the mold, or

by any of the usual means of packing; and

to prevent a too sudden cooling of the molten metal when poured upon the surface of the piston, the upper surface thereof may be made of re brick or clay, soapstone, or any suitable non conducting material, as shown. There may be two air and water pipes, as shown in the sketch at O and D, or one, C, may be made to answer for both.

The operation of casting is thus conducted: Before admitting the metal to the mold the piston B is raised or forced up to within a suitable distance from the top of the mold, and maintained in position by the pressure of the air beneath it. The metal is then poured or allowed, by suitable valves in a casting-ladle, to drop upon the top of the piston, and simultaneously with its flow the cock c in the airpipe C is opened to an extent just sufficient to allow the descent of the piston B to correspond with the influx of metal above it, so

that the level of the metal at the top of the mold shall remain continuously the same or nearly so, the molten metal gradually iiowing down through that already cast and outward against the sides of the mold as the piston descends until the ingot is made of the length required. In case the piston B should have a tendency to become clogged, or should for any cause fail to descend as rapidly as should' be desired, the air beneath it might be eX- hausted through the pipe O, and thus the descent of the piston be facilitated. Immediately the metal proposed to be cast has been poured in a stream of water should be turned upon the outside of the mold, so as to chill it as quickly as possible; and as soon as the ingot has become set it may be expelled from the mold by a stream of water forced in at D or O, and making of the mold a hydraulic rain or forcing press; or in case it is found preferable to use a jointed mold, as shown in Fig. 3, the mold may be taken apart and the ingot removed somewhat, as is usual in casting steel.

In the common modes of casting steel and other ingots it is usual to pour the molten metal upon the bottom of the mold and ll it by the gradual rise of the metal as it is introduced. This method has been found objecl tionable, especially when ingots of considerable length are desired, because, in the first place, the molten metal as it falls into the mold is apt to strike the sides of the mold in its descent, or to rebound from the bottom of the mold or surface of the metal therein and strike against the sides of the mold, thus producing a rough surface in the mold, and causing the casting made thereby to be rough and unsound on its outside; and, secondly, when the stream of metal falls through any considerable distance its surface has a tendency to absorb oxygen from the air, and the current of metal draws down with it into the molten mass in the mold a greater or less quantity of the surrounding air or gas, thus producing a porous or unsound ingot.

Several remedies for these difficulties have been proposed, one being to cover the top of the mold and exhaust the air and gases from it while the metal is flowing therein, another being to fill the mold from below by a duct or pipe introduced at the bottom of the mold and risingon the outside above what l their bottoms or the supplementary bottoms is to be the top of the proposed ingot; and it has also been proposed to solidify ingots cast as above by compressing them while in the mold, and While in a fiuid or pasty condition, by means of a hydraulic ram constructed within the mold. 1

The rst plan has not, so far as I have learned, been found to be practicable, and by the second it is necessary to produce two ingots for every particular one required; and by neither of the above plans, more than by the ordinary methods, is it possible with convenience and certainty to cast very long ingots, so that when long1 shafts are required it is usual to cast a comparatively short ingot of large diameter, and then to extend it under hammers or rolls to the length required, whereas it will be seen that by my plan an ingot of any probably desirable length may easily be made.

As aforementioned, I am aware that it is not new to construct molds for casting ingots in such wise as that when cast the ingots may be compressed in the molds or be removedv therefrom by hydraulic power applied beneath or pistons within the molds; and though the apparatus I employ is adapted in part to these purposes, I do not claim any such construction of or use Of molds; but

What I do claim as my invention, and desire to secure by-Letters Patent, is-

rIhe mode of casting ingots of steel or other metals by pouring or tapping such metals upon a piston in a mold so arranged and constructed that as the metal is continuously in- 

